The present invention relates to laminated cables and cablewraps. In particular, the present invention relates to electro-optical laminated cables and cablewraps for routing to mobile electrical and optical devices.
In many systems containing both electrical and optical devices, the electrical and optical devices are mobile. For example, on a satellite electrical and optical devices may be gimbaled (e.g., rotatably mounted) to the satellite so that they can be pointed and rotated. In such a case, it is necessary to provide a cable for communicating between the gimbaled electrical and optical devices and other electrical and optical devices on board the satellite. Such other electrical and optical devices may include electrical and optical devices on a satellite""s payload that gather data from terrestrial or non-terrestrial targets.
Past systems have primarily utilized coaxial designs for containing electrical conductors. Past systems have also utilized coaxial designs for separately containing fiber optic elements. Systems used in the past have several drawbacks, however. As a result of the coaxial designs, a large resistive torque is provided against the rotating mechanism. This is, in part, because electrically insulated and shielded conductors are heavy, stiff, and have high friction coefficients. Moreover, many existing fiber optic insulated and shielded elements are heavy, stiff, and have high friction coefficients.
As a result of the high torque placed on rotating mechanisms by cables used in the past, motors would have to use a substantial amount of power just to move the cables connecting the rotating mechanism to the satellite (for example 50% or more of a motor""s power). As a result, system efficiency was greatly reduced and larger motors were required to move the rotating mechanism. The large torque created by such cables also resulted in a larger overall weight of the system (and motor), further decreasing system efficiency.
One present system, presented in U.S. Pat. No. 5,878,180 to Nothofer et al., discloses a hybrid cable, containing stacks of optical fiber ribbons contained within a central optical fiber element, and electrical conductor elements twisted around the central optical fiber element. Because the Nothofer system is coaxial in form, however, it contains the shortcomings of the prior art.
A need has long existed in the industry for a low-torque laminated cable and cablewrap. A need has also long existed in the industry for a low-friction laminated cable and cablewrap. A need has further long existed in the industry for a hybrid cable and cablewrap for facilitating communication between both electrical and optical devices and mobile or rotatable electrical and optical devices.
It is an object of the present invention to provide an improved electro-optical cable and cablewrap.
It is a further object of the present invention to provide a low-torque cable and cablewrap for use with electro-optical systems.
It is an additional object of the present invention to provide a cable and cablewrap for transmitting electrical and optical signals across a rotating interface.
It is yet another object of the present invention to provide an improved cable and cablewrap for use in a moving mechanical assembly.
It is a further object of the present invention to provide a low-torque electro-optical cable capable of being oriented in a clock-spring like configuration and creating a relatively low torque when coiled and uncoiled.
It is an additional object of the present invention to provide a cable and cablewrap which permits optical and electrical transmissions between a gimbaled satellite payload and electrical and optical devices on the satellite proper.
It is a still further object of the present invention to provide a cable and cablewrap for connection to Optical Inter-Satellite Link (xe2x80x9cOISLxe2x80x9d) communication devices.
One aspect of the present invention is an elongated electro-optical cable including a plurality of elongated electrical conductors, a plurality of fiber optic elements, and an elongated insulating film casing enveloping the plurality of electrical conductors and the plurality of fiber optic elements. The fiber optic elements, electrical conductors, and the elongated insulating film casing are arranged to form a generally flat laminated cable.
Another aspect of the present invention is a method for making an elongated electro-optical cable including insulating a sheet of a plurality of shielded elongated electrical conductors, affixing a sheet of a plurality of fiber optic elements to the insulated electrical conductors, and insulating the fiber optic elements. The step of affixing a sheet of fiber optic elements may occur before or after the insulating step.